Ice-skating grinding apparatus

ABSTRACT

A grinding apparatus for sharpening the edges of ice skates employing a conoidal abrasive element and aligning means for grinding a symmetrical arcuate surface of a desired uniform concavity on the edge of an ice skate blade.

United States Patent Inventor Leo l. Norgiel 7621 W. Morrow Circle, Dearborn, Mich. 48126 Appl. No. 807,180

Filed Mar. 14, 1969 Patented Aug. 10, 1971 ICE-SKATING GRINDING APPARATUS 2 Claims, 12 Drawing Figs.

US. Cl 51/102, 51/205 WG, 51/228, 76/83 Int. Cl B24b 9/04, B21k 17/00 Field oISearch 1; 51/102, 128, 205 WG, 228, 327; 76/83 [56] References Cited UNITED STATES PATENTS 1,480,422 1/1924 Strom 51/228 3,164,932 l/I965 Morith .1 76/83 X 1,153,993 9/1915 Barker 51/228 912,757 2/1909 Thompson... 51/228 726,974 S/l903 McLeran 51/102 Primary Examiner-Harold D. Whitehead Attorney-Harness, Dickey & Pierce ABSTRACT: A grinding apparatus for sharpening the edges of ice skates employing a conoidal abrasive element and aligning means for grinding a symmetrical arcuate surface of a desired uniform concavity on the edge ofan ice skate blade.

Patented Aug. 10, 1971 2 Sheets-Sheet I INVENTOR. A60 1/1/0728 BY ICE-SKATING GRINDING APPARATUS BACKGROUND OF THE INVENTION Ice skating as a form of recreation and sport is receiving increased popularity as evidenced by an increased number of public and private skating rinks and clubs. Manufacturers of ice skates supply ice skates in the three basic popular types, namely: figure skates, hockey skates and racing skates. Regardless of the specific type, ice skates as shipped from the factory are all properly sharpened and are conventionally pro vided with hollow-ground blade edges.

During the use of ice skates, it is periodically necessary to perform a resharpening thereofin order to maintain optimum skating performance associated with properly sharpened blades. Conventionally, sharpening techniques of the types heretofore known require a series of distinct separate sharpening operations to be performed on each skate blade in order to remove the nicks and indentations from the skate edge, as well as to restore the proper uniform hollow-ground skating edge surface. In accordance with conventional sharpening techniques,'skate blades are first subjected to a cross-grinding operation employing a relatively course grit wheel, which frequently must be dressed to retain a substantially perfect cylindrical peripheral contour. Thereafter, the cross-ground blade is subjected to a parallel grinding operation using a relatively large wheel having a convex face, which is ofa finer grit for removing the grinding marks left by the preceding crossgrinding operation and effects appropriate contouring of the hollow-ground blade edge. In order to provide the desired concavity of the resultant ground skating edge, it is necessary that the convex grinding face of the circular parallel grinding wheel be frequently dressed to the proper radius to assure uniformity in the curvature of the finished blade. Finally. any residual burrs along the parallel edges of the skate blade edge are removed by hand honing.

The equipment necessary to perform the several grinding operations is relatively expensive and space consuming and requires a relatively skilled operator to perform a proper grinding operation, as well as the periodic dressing of the grinding wheels used. In addition, the degree of concavity of the hollow-ground blade edge preferably is varied between the several types of ice skates to provide optimum performance and, accordingly, to accommodate such variations, it is necessary that grinding wheels of different diameters and different convex grinding faces be available to achieve proper sharpening of each skate type. The duplication of equipment necessitated and/or the tedious and time-consuming operation of replacing grinding wheels to adapt them to a specific skatesharpening operation has resulted in a substantial increase in the cost of skate sharpening. More usually,'only one set of grinding wheels are used, which are selected as a compromise between the several optimum types, resulting in skate blades which do not perform at their optimum design level. Due to the cost and space requirements of proper equipment for sharpening ice skates, most skating rinks and skating clubs are forced, due to economic considerations and the lack of skilled operators, to perform sharpening operations on ice skates of their patrons or members which fall far short of providing a properly sharpened blade, such as originally received from the factory.

The foregoing problems and disadvantages are overcome in accordance with the grinding apparatus of the present invention which effects, on one operation, the formation of an appropriately contoured hollow-ground surface along a skating edge and which is readily adaptable to sharpening skates of the several different types without necessitating a substitution of grinding wheels.

SUMMARY OF THE INVENTION The benefits and advantages of the present invention are provided by a grinding apparatus which comprises in combination a framework and a supporting fixture for mounting and securing an ice skate blade thereto in a position in which the centerline of he edge thereof to be hollow-ground is disposed in a firstplane. A conoidal abrasive element having an outward convex surface is supported on a spindle rotatably mounted on the frame for rotation about an axis which is disposed in a second plane positioned substantially parallel to the first plane in which the centerline of the skate blade is disposed. Adjusting means are provided on the frame for varying the distance between the abrasive element and the blade supported on the supporting fixture to effect a coincidence between the first and second planes, assuring centralization of the grinding surface of the conoidal abrasive element with the center of the skate blade edge. Suitable aligning means, preferably adapted to coact with the skate blade, are provided which, upon proper alignment, indicate a state of proper alignment to the operator. The radius of curvature of theskate edge being ground can be readily controlled by the operator by employing selected peripheral portions of the conoidal abrasive element, thereby achieving an optimum sharpening operation for each of the several skate blade types.

Additional advantages and benefits of the grinding apparatus comprising the present invention will become apparent upon the reading of the description of the preferred embodiments, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of the grinding apparatus constructed in accordance with the preferred embodiments of the present invention and illustrating a skate blade on the supporting fixture undergoing a sharpening operation;

FIG. 2 is a transverse vertical sectional view partly magnified, illustrating the frame and vertically adjustable motor for rotating the conoidal abrasive element;

FIG. 3 isa magnified side elevational view of the skate bladesupporting fixture with a blade positioned thereon as shown in phantom;

FIG. 4 is a plan view of the supporting fixture shown in FIG.

FIG. 5 is a transverse vertical sectional view through the skate blade-supporting fixture shown in FIG. 3, and as viewed substantially along the line 5-5 thereof;

FIG. 6 is an enlarged side elevational view of the conoidal abrasive element of the grinding apparatus shown in FIG. 1;

FIGS. 7 through 9, inclusive, are magnified fragmentary cross-sectional views illustrating selected variations in the degree of curvature and depth of hollow-ground skate blade edges attainable in accordance with the grinding apparatus of the present invention;

FIG. 10 is an enlarged side elcvational view of the aligning device;

FIG. 11 is a fragmentary transverse vertical sectional view through the aligning device shown in FIG. 10, and taken substantially along the line 11- thereof; and

FIG. 12 is a fragmentary transverse vertical sectional view through the aligning device shown in FIG. 10 and taken substantially along the line 12-12 thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings, and as may be best seen in FIG. I, the grinding apparatus of the present invention consists of a frame or base 20, which is relatively rigid and of high strength, such as a cast iron frame, for example, of which a portion of the upper surface, as indicated at 22, is machined so as to provide a faceplate which is smooth and flat and on which a skate blade-supporting fixture 24 is adapted to be movably supported. Mounted on the frame 20 adjacent to the faceplate 22, as shown in FIG. 2, is a pair of guide posts 26, which are oriented substantially perpendicular to the plane of the faceplate and on which a crosshead 28 is slidabley and guidably mounted. Rigidly secured to and projecting forwardly of the face of the crosshead 28 is a motor housing 30,

within which a suitable electric motor 32 is secured. To the projecting end of a shaft or spindle 34 of the motor 32, a conoidal abrasive element 36 is secured with its axis in alignment with the axis of the shaft 34. The axis of the abrasive element 36 is disposed in a plane which is positioned substantially parallel to the plane of the faceplate 22 for a purpose subsequently to be described.

As shown in FIGS. 1 and 2, the upper ends of the guide posts 26 are securely bolted to the end portions of a crossmember 38, which is formed at substantially the midpoint thereof with an aperture around which a thrust washer 40 is mounted. A lead screw 42 is secured at its lower end, such as by means of a set screw 44 and a collar 46, to the upper surface of the crosshead 28, and extends substantially vertically upwardly therefrom through the thrust washer 40. A handwheel 48 is disposed in threaded engagement on the lead screw 42 and is positioned with its lower surface in sliding bearing contact against the upper surface of the thrust washer 40.

In accordance with the arrangement as illustrated in FIGS. 1 and 2, rotation of the handwheel 48 effects vertical movement of the crosshead 28 and the conoidal abrasive element 36 rotatably supported thereon in a vertical direction relative to the surface or plane of the faceplate 22. The weight of the crosshead and the motor housing thereon continuously urges the crosshead downwardly such that the lower surface of the handwheel is always disposed in firm bearing contact against the upper surface of the thrust washer, enabling minute adjustments of the relative disposition of the axis of the abrasive element with respect to a skate blade supported on the supporting fixture 24.

The supporting fixture 24, as shown in FIGS. 1, 3, 4 and 5, comprises a base 50 provided with a machined flat lower surface 52, which is adapted to be disposed in sliding guided con tact on the surface of the faceplate 22 during manipulation of a skate blade during a grinding operation. An upwardly extending flange 54 is rigidly affixed to the base 50 and preferably is formed with a slight arcuate curvature, as best seen in FIG. 4, along its upper edge approaching a curvature conventionally encountered along the edge of skate blades, A mounting surface 56 is provided along the upper edge of the flange 54 which is accurately machined so as to be parallel longitudinally and transversely with the lower surface 52 and correspondingly with the surface of the face plate 22.

A plurality of tapped apertures 58 are provided at spaced intervals along the mounting surface 56 for threadably receiving the threaded shank portions of screws 60, 62. An L-shaped clamping member 64 is provided with an aperture through which the screw 60 extends and is adapted to overlie a stanchion of a skate blade, as shown in phantom in FIG. 3 and indicated at 66. Similarly, a flat clamping plate 68 is provided with an aperture through which the screw 62 extends for over lying a stanchion along the forward edge of the skate blade 66.

In accordance with the arrangement illustrated, the supporting fixture 24 is operative to removably clamp the skate blade 66 in the positions as shown in FIGS. 3 and by means of the clamping members 64 and68, wherein the skating edge 70 thereof is disposed substantially perpendicular to the plane of the surface of the face plate 22, and wherein the centerline of the skating edge 70 is positioned in a plane disposed substantially parallel to the faceplate.

The conoidal abrasive element 36, as best seen in FIG. 6, is of a generally cone-shaped configuration and is provided with an outward convex configuration along the grinding surface thereof. The arcuate curvature of the grinding surface of the abrasive element is important to enable selected segments to the grinding wheel to be contacted by a blade during the sharpening operation, thereby providing a desired radius of curvature to the hollow-ground skate edge. Generally. a degree of curvature corresponding to a radius of about 5 inches to about inches for a wheel having a maximum operative diameter of about 3 inches has been found satisfactory for most purposes. Alternatively, the degree of curvature can be expressed in terms of an arcuate taper as represented by a line disposed tangent to substantially the center of the surface of the conoidal abrasive element, providing an arcuate taper at each end thereof of from about one-sixteenth to about one-eighth inch. The magnitude of curvature that is necessary is one such that only a restricted longitudinal length of the grinding wheel face is in contact with a skate edge being sharpened.

The conoidal abrasive element 36 may be composed of any one of a variety of bonded abrasive compositions conventionally employed in the manufacture of grinding wheels and preferably incorporates abrasive particles of a size ranging from about to about grit. The foregoing grit size has been found to provide a relatively smooth surface finish on the hollowground surface of skate blade edges without necessitating any subsequent parallel grinding.

The conoidal abrasive element, as shown in FIG. 6, has been subdivided into bands or zones designated, respectively, by the letters A, B and C. Each of these zones represents a desired diameter for imparting a desired radius ofcurvature to a skate blade according to the specific type of blade being sharpened. As an example, reference is made to FIGS. 7-9 in which three skate blade edges are shown which are provided with a different radius of curvature along their skating edges. In FIG. 7, a skate blade 72 is shown in which the hollowground surface 74 thereof is of a relatively shallow depth and of a relatively large radius. THe configuration as shown in FIG. 7 is typical of the optimum contour of a hollow-ground -skate blade used in Figure skating in which the maximum depth of the hollow-ground surface 74 is in the neighborhood of about 0.0015 inch. The attainment of the arcuate contour represented by the skate blade edge shown in FIG. 7 is achieved by using zone C of the conoidal abrasive element illustrated in FIG. 6. For most purposes, zone C has an average diameter of about 3 inches, which in turn provides the desired curvature of hollow-ground blades of the figure skating type which usually range in thickness of from about 0.100 to about 0.180 inch.

Similarly, a skate blade 76 is shown in FIG. 8, in which the hollow-ground surface 78 thereof is ofa greater depth and ofa smaller radius of curvature than the surface 74 shown in FIG. 7. THe contour of the hollow-ground surface of the skate blade shown in FIG. 8 is typical of the optimum skating edge for figure skates which are used primarily for dancing wherein the depth of the hollow-ground surface 78 relative to the skate edges is preferably about 0.0025 inch. In order to achieve the contour as illustrated in FIG. 8, such skates are sharpened employing the zone or band B of the conoidal abrasive element shown in FIG. 6, which generally has an average diameter of about 1.6 1.7 inches.

A third type of skate edge contour is illustrated by the hollow-ground surface 80 of the skate blade 82 shown in FIG. 9, which is typical of that employed in free skating of various types. In blades ofthis particular type of ice skate, the depth of' the hollow-ground surface 80 is deeper and ofa smaller radius of curvature than the two skate blade contours illustrated in FIGS. 7 and 8. Generally, a maximum depth of about 0.005 inch is preferred for most instances which is achieved by employing zone A of the conoidal abrasive element 36 shown in FIG. 6 during the sharpening operation.

It will also be apparent from the foregoing that a variation in the depth and radius of curvature of the hollow-ground surface of an ice skate blade can be provided along the length thereof to achieve optimum skating characteristics by utilizing different grinding zones of the conoidal grinding element. This can be achieved in a smooth transitional shift from one zone to the next zone by an operator as the skate blade edge is moved relative to the grinding face of the abrasive element.

In order to assure that the hollow-ground surface along the edge of the skate blade is positioned symmetrically with respect to the centerline thereof, the plane passing through the centerline of the skate edge must coincide with the plane passing through the axis of the conoidal abrasive element. As previously described, this is achieved by raising and lowering the crosshead 28 by manipulation of the hand wheel 48 to ef-' fect such coincidence. Such adjustments are necessary to compensate for skate blades of different thickness which usually vary from about 0.100 up to about 0.1 80 inch.

In order to facilitate an alignment of the plane passing through the centerline of the skate blade edge and the plane passing through the axis of the abrasive element, the grinding apparatus of the present invention is preferably provided with an aligning device, such as the alignment assembly indicated at 84 in FIG. 1. The alignment assembly 84, as best seen in FIGS. l012, comprises an aligning or centralizing bar 86 which is formed at one end thereof with a tapered alignment notch 88 for removably receiving the edge of a skate blade mounted on the supporting fixture 24. The alignment notch 88 is of a progressively decreasing width on movement from the outer end toward the inner end thereof, so as to accommodate skate blades of the various widths customarily encountered.

The alignment bar 86 is pivotally secured to the side of the motor housing 30 which is formed with a flattened surface 90, against which the inner surface of the alignment bar is disposed. The pivoting connection is achieved by a pivot screw 92, as seen in FIG. ll, having a reduced threaded shank portion 94 disposed in threaded engagement in an aperture of the housing and a smooth unthreaded enlarged shank portion which projects outwardly there from and extends through an aperture 96 provided at substantially the midpoint of the alignment bar. A compressiontype coil spring 98 is disposed in encircling relationship around the projecting end portion of the pivot screw 92 and is disposed with one end in abutment against the head portion of the pivot screw and the other end in bearing contact against the outer surface of the alignment bar, biasing it toward bearing contact against the flattened surface 90. v

A latching device, as best seen in FIGS. and 12, is provided on the alignment bar on the end portion opposite to the alignment notch for indicating to an operator when a proper alignment between the abrasive element and skate edge is attained. As shown in FIG. 12, the latching device comprises a flanged tubular member 100 which is mounted on the outer surface of the alignment bar and has an inner bore 102 which is disposed in axial alignment with an aperture 104 extending through the alignment bar. The diameter of the pin 106 relative to the aperture 104 and inner bore 102 is controlled to provide a close clearance fit, enabling reciprocating movement of the pin to and from a retracted position within the inner bore 102 and aperture 104 and a projection position as shown in solid lines in which the projecting end thereof is disposed in engagement in an alignment bore 108 formed in the housing. In order to achieve a release of the pin from the alignment bore, a rod 110 is threadably engaged at one end thereof in the pin 106 and is formed with a knob [12 at the outer end thereof. A coil spring 114 is positioned within the tubular member 100 and is disposed in seated engagement against the pin 106 at one end and the shoulder formed on the tubular member 100 at the other end thereof. In accordance with this arrangement, the pin 106 is continuously biased toward the housing and is adapted to snap into the alignment bore 108 when appropriate adjustment of the disposition of the grinding element and skate blade edge are attained signifying the attainment of proper alignment. It will be further noted that the centerline of the alignment notch 88, when the alignment bar is latched by the pin 106, is disposed in alignment with the plane containing the axis of the conoidal abrasive element.

In operation, a skate blade to be sharpened is securely clamped on the mounting surface 56 ofthe supporting fixture.

curvature of the flange 54 of the supporting fixture as shown in FIG. 5. Thereafter, the supporting fixture is placed on the surface of the faceplate 22 and is moved toward engagement with the alignment notch-88 of the alignment device. The

alignment device is released by withdrawing the'pin 106 from the alignment bore, enabling unrestricted pivoting movement of the alignment bar consistent with the relative disposition of the skate blade engaged within the alignment notch. Thereafter, the handwhcel (FIGS. 1 and 2) is manipulated to effect up or down movement of the crosshead and a corresponding pivoting movemcnt of the aligning bar until the end of the alignment pin 106 is positioned in alignment with the bore 108, causing the spring 114 to latch the pin, signifying the attainment ofan aligned condition. The motor of the grinding apparatus is then energized and the operator, by selecting the appropriate grinding zone of the wheel to be used consistent with the specific skate type being sharpened, effects a movement of the blade along its edge with the selected grinding zone imparting a uniform symmetrical hollow-ground contour to the skating edge. Any residual burrs along the skating edge can readily be removed such as by hand honingv it will be appreciated that while the description of the preferred embodiments of the present invention are well calculated to achieve the advantages and benefits as herein described, the invention is susceptible to modification, variation and change without departing from the spirit thereof.

What I claim is:

l. A grinding apparatus comprising in combination a frame, supporting means for supporting a skate blade to be sharpened with the centerline of the edge thereof disposed in a first plane, a conoidal abrasive element rotatably mounted on said frame for rotation about its axis, said axis disposed in a second plane parallel to said first plane, adjusting means for adjusting the distance between said abrasive element and the blade for effecting coincidence between said first and said second plane, and alignment means on said frame to facilitate adjustment for effecting coincidence of said first and said second plane, said aligning means comprising a member pivotally mounted on said frame for movement between an aligned position corresponding to coincidence between said first and said second plane and a nonaligned position spaced therefrom, coacting means on said member for engaging the edge of a blade on said supporting means and sensing the position thereof, and indicating means for indicating when said member is disposed in said aligned position.

2. A grinding apparatus comprising in combination a frame, supporting means for supporting a skate blade to be sharpened with the centerline of the edge thereof disposed in a first plane, a conoidal abrasive element rotatably mounted on said frame for rotation about its axis, said axis disposed in a second plane parallel to said first plane, adjusting means for adjusting the distance between said abrasive element and the blade for effecting coincidence between said first and said second plane, and alignment means on said frame to facilitate adjustment for effecting coincidence of said first and said second plane, said aligning means comprising of a member pivotally mounted on said frame, said member formed with an aligning notch for removably receiving the edge of a blade on said sup porting means, and latching means for restricting pivoting movement of said member when said aligning notch is disposed in coincidence with said first and said second plane. 

1. A grinding apparatus comprising in combination a frame, supporting means for supporting a skate blade to be sharpened with the centerline of the edge thereof disposed in a first plane, a conoidal abrasive element rotatably mounted on said frame for rotation about its axis, said axis disposed in a second plane parallel to said first plane, adjusting means for adjusting the distance between said abrasive element and the blade for effecting coincidence between said first and said second plane, and alignment means on said frame to facilitate adjustment for effecting coincidence of said first and said second plane, said aligning means comprising a member pivotally mounted on said frame for movement between an aligned position corresponding to coincidence between said first and said second plane and a nonaligned position spaced therefrom, coacting means on said member for engaging the edge of a blade on said supporting means And sensing the position thereof, and indicating means for indicating when said member is disposed in said aligned position.
 2. A grinding apparatus comprising in combination a frame, supporting means for supporting a skate blade to be sharpened with the centerline of the edge thereof disposed in a first plane, a conoidal abrasive element rotatably mounted on said frame for rotation about its axis, said axis disposed in a second plane parallel to said first plane, adjusting means for adjusting the distance between said abrasive element and the blade for effecting coincidence between said first and said second plane, and alignment means on said frame to facilitate adjustment for effecting coincidence of said first and said second plane, said aligning means comprising a member pivotally mounted on said frame, said member formed with an aligning notch for removably receiving the edge of a blade on said supporting means, and latching means for restricting pivoting movement of said member when said aligning notch is disposed in coincidence with said first and said second plane. 